Project Summary For more than two decades, U.S. affordable housing policy has centered on redeveloping public housing complexes into mixed-income communities and providing public housing residents with vouchers to relocate to subsidized housing in the private housing market. The health impacts of this housing strategy have been evaluated in studies that neither investigate their impacts on opioid and other drug abuse in contexts where there have been longstanding opioid epidemics, nor have they determined whether relocating to other neighborhoods, including to those with better amenities, is more beneficial to health than remaining in communities that are redeveloping. The proposed study will be among the first prospective investigations of the impacts of public housing redevelopment on opioid and other drug abuse and related health outcomes (e.g., HIV, HCV, mental disorders) among residents who remain in a redeveloping community (n=125) and residents who relocate from a redeveloping community (n=125), relative to residents who remain in a non- redeveloping comparison public housing community (n=125). We will adapt and refine our recruitment and retention strategies to establish the three sub-cohorts of public housing residents and apply rigorous (e.g., propensity scores) and innovative methodologies (e.g., walking ethnographies) to accomplish the following specific aims: Aim 1a: Assess similarities and differences in opioid and other drug abuse, related health outcomes (HCV, HIV, mental disorders), health service use (e.g., drug treatment), and micro-level environmental conditions (e.g., social, housing, neighborhood) among the three sub-samples of public housing residents prior to redevelopment (e.g., new construction, relocation, etc.) Aim 1b: Evaluate initial impacts of residing in the redeveloping community and of relocating from the redeveloping community, relative to residing in the non-developing community on opioid and other drug abuse and related outcomes, one-year post enrollment Aim 2: Elicit narratives on micro-level environmental conditions and health among 20 adults from each sub-cohort prior to redevelopment and one-year post enrollment. By accomplishing these aims we will establish sub-cohorts for a novel R01 that will strengthen evidence on the impact of affordable housing policies on opioid and other drug abuse and related outcomes, and inform how future housing policies in Baltimore and other cities can be designed to be more health-promoting. The strong team of collaborators with expertise in establishing cohorts of hard-to-reach populations and public housing residents, ethnographic research, and causal inference, will increase feasibility, rigor and successful achievement of the proposed aims.